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  2. pandas (software) - Wikipedia

    en.wikipedia.org/wiki/Pandas_(software)

    If data is a Series, then data['a'] returns all values with the index value of a. However, if data is a DataFrame, then data['a'] returns all values in the column(s) named a. To avoid this ambiguity, Pandas supports the syntax data.loc['a'] as an alternative way to filter using the index. Pandas also supports the syntax data.iloc[n], which ...

  3. Aggregate function - Wikipedia

    en.wikipedia.org/wiki/Aggregate_function

    Sum; Others include: Nanmean (mean ignoring NaN values, also known as "nil" or "null") Stddev; Formally, an aggregate function takes as input a set, a multiset (bag), or a list from some input domain I and outputs an element of an output domain O. [1] The input and output domains may be the same, such as for SUM, or may be different, such as ...

  4. Fenwick tree - Wikipedia

    en.wikipedia.org/wiki/Fenwick_tree

    A Fenwick tree or binary indexed tree (BIT) is a data structure that stores an array of values and can efficiently compute prefix sums of the values and update the values. It also supports an efficient rank-search operation for finding the longest prefix whose sum is no more than a specified value.

  5. Self-descriptive number - Wikipedia

    en.wikipedia.org/wiki/Self-descriptive_number

    From the numbers listed in the table, it would seem that all self-descriptive numbers have digit sums equal to their base, and that they're multiples of that base. The first fact follows trivially from the fact that the digit sum equals the total number of digits, which is equal to the base, from the definition of self-descriptive number.

  6. Anscombe's quartet - Wikipedia

    en.wikipedia.org/wiki/Anscombe's_quartet

    Value Accuracy Mean of x: 9 exact Sample variance of x: s 2 x: 11 exact Mean of y: 7.50 to 2 decimal places Sample variance of y: s 2 y: 4.125 ±0.003 Correlation between x and y: 0.816 to 3 decimal places Linear regression line y = 3.00 + 0.500x: to 2 and 3 decimal places, respectively Coefficient of determination of the linear regression:

  7. Spearman's rank correlation coefficient - Wikipedia

    en.wikipedia.org/wiki/Spearman's_rank_correlation...

    Python has many different implementations of the spearman correlation statistic: it can be computed with the spearmanr function of the scipy.stats module, as well as with the DataFrame.corr(method='spearman') method from the pandas library, and the corr(x, y, method='spearman') function from the statistical package pingouin.

  8. Row- and column-major order - Wikipedia

    en.wikipedia.org/wiki/Row-_and_column-major_order

    For matrices in mathematical notation, the first index indicates the row, and the second indicates the column, e.g., given a matrix , the entry , is in its first row and second column. This convention is carried over to the syntax in programming languages, [ 2 ] although often with indexes starting at 0 instead of 1.

  9. Kahan summation algorithm - Wikipedia

    en.wikipedia.org/wiki/Kahan_summation_algorithm

    The algorithm performs summation with two accumulators: sum holds the sum, and c accumulates the parts not assimilated into sum, to nudge the low-order part of sum the next time around. Thus the summation proceeds with "guard digits" in c , which is better than not having any, but is not as good as performing the calculations with double the ...